Rotary pump.



No. 704,224. Patented July 8, I902.

W. W. WAINWBIGHT.

ROTARY PUMP.

(Application filed Jan. 1,

(No llodel.)

Inventor Wit asses:

7 UNITED STATES PATENT OFFICE.

IVILLIAM IV. VVAINW'RIGHT, OF OONNERSVILLE, INDIANA, ASSIGNOR TO THE P. II. 85 F. M. ROOTS COMPANY, OF OONNERSVILLE, INDIANA.

ROTARY PUMP.

SPECIFICATION forming part of Letters Patent No. 704,224, dated July 8, 1902. Application filed January 11,1902, $erial No. 89,366. (No model.)

To (all whom, it may concern:

Be it known that 1, WILLIAM W. WAIN- WRIGHT, a citizen of the United States, residing at Connersville, Fayettecounty, Indiana, (post-ofiice address, care P. H. & F. M. Roots Company, Connersville, Indiana,) have invented certain new and useful Improvements in Rotary Pumps, of which the following is a specification.

Thisinvention, pertaining to rotary pumps, will be readily understood from the following description, taken in connection with the acoompanying drawings, in which Figure l is a vertical transverse section of a rotary pump exemplifying my present invention, and Fig. 2 a side elevation thereof.

In the drawings, 1 indicates the casing of the pump, having a form usual in rotary pumps involving lobed impellers on parallel shafts; 2, the inlet thereto; 8, the outlet from the casing; 4, the usual heads of the casing; 5, the usual impellershafts, journaled in the casing-heads parallel with each other andextending longitudinally through the casing; 6, lobed impellers fast on the shafts and cooperating with each other and with the inwall of the casing; 7, an air-chamber disposed at one side of the casing immediately against the same and at one side of the inlet 2, the casing forming the inner wall of this air-chamber; 8, a similar air-chamber at the other side of the casing and inlet; 9, the inlets to the two air chambers, the same leading from pump-inlet 2 at a point as close as practicable to the inwall of the casing where the inlet passes therethrough; 10, the base of the easing, the same being illustrated as separably united to the main portion of the casing, and 11 the outer walls of the air-chambers.

In pumps of this class there is a starting and stopping of the flow at the inlet four times at each revolution, as the direction of current through the pump is shifted from one side to the other of the casing as the respective impellers begin their discharging work. This change of direction and consequent momentary stoppage of inlet-flow causes severe vibrations of a character destructive to pumps and foundations. The air-chambers 7 and 8 in my present construction have a combined area equal to the area of the pump-inlet, and

the flow through the inlet-pipe may be constant up to the entrance of the air-chambers. During the period of shifting and momentary stoppage of fiow to the pump the water not required may pass into the appropriate airchamber and be given out again as the flow recommences in the opposite direction, thus limiting the amount of water to be started and stopped to'a very small column, the result being a practically smooth Working. The disposition of the air-chambers permits their connections with the inlet to be exceedingly close to the inwall of the pump, the separation being represented by the mere thickness of the wall of the casing. The outer Walls of these air-chambers may beconnected with the wall of the casing in any desired manner, but preferably by casting them with the easing, as illustrated, the separable character of the base 10 facilitating the coring of the airchambers, and this separable characteristic of the base is also of merit if the outer walls of the air-chambers instead of being cast upon the casing are bolted or riveted thereto. The air-chambers extend the entire length of the casing and their structure serves in reinforc ing the casing.

I claim as my invention 1. In a rotary pump, the combination, substantially as set forth,'of a casing having an inlet and an outlet, a pair of lobed impellers mounted in the casing, and a pair of separate air-chambers connected with opposite sides of the single pump-inlet at the point where the latter enters the casing and disposed substantially in the plane of rotation of the impellers.

2. In a rotary pump, the combination, substantially as set forth, of a casing having an inlet and an outlet, a pair of lobed impellers mounted in the casing, and outer walls joining the casing and in conjunction therewith forming separate air-chambers having connection with the single pump-inlet at the point where the latter enters the casing, said separate air-chambers being oppositely disposed in substantially the plane of rotation of the impellers.

3. In a rotary pump, the combination, substantially as set forth, of a casing having an inlet and an outlet, a pair of lobed impellers mounted in the casing, a base separably secured t0 the casing at the inlet thereto, and outer walls connected with the casing and the base and in conjunction therewith forming separate air-chambers at the opposite sides of the inlet in substantially the plane of rotation of the impellers and having conneetion therewith at the point where the single inlet enters the casing.

WILLIAM WV. WVAINWRIGHT.

WVitnesses:

GEO. C. HICKS, J12, E. D. JOHNSTON. 

